Typical prior art absorbers utilize what is described herein as a static, fixed surface area on which the absorption occurs. For example, a common absorber design is a “shaped packing” design. In this design, packing elements with complex surface shapes are placed in a fixed size chamber. A liquid solvent is typically caused to flow downwardly and wet the fixed size exterior surfaces of the elements. This provides a large surface area for mass transfer between the solvent and the gas. A gas is then driven upwardly through the packing, and a selected component of the gas is absorbed into the surface of the solvent. The surface area of the packing remains fixed and static. The three commercial types of packing are random, structured trays, and spray towers. The fixed and static surface area is a major limitation of the prior art.
Another common limitation of known absorbers is the relatively short amount of time in which the two fluids are in surface contact with each other. The prior art designs typically use a counter-flow arrangement wherein the solvent in the above specific shaped packing example flows downwardly and the gas flows upwardly. The counter-flow technique is utilized to maximize the concentration gradient between the two fluids but has the inherent limitation of minimizing the time in which the surfaces of the two fluids are in contact.
A further limitation of these conventional packings is the significant height of packing required to facilitate the absorption process. A further limitation of most prior art absorbers is that they require relatively expensive materials in their construction. The large surface area of these packings which is required to facilitate absorption also makes them susceptible to fouling where the surfaces can become fouled with dirt, impurities from the gas or liquid or precipitation products from the absorption itself.
The present invention overcomes all of the above limitations of the prior art.